Tandy TRS-80 Owner Manual & Programming Manual page 76

APPENDIX
B.
CHAPTER CHECKPOINT ANSWERS
CHAPTER
2
1.
Unless the disk
has been
formatted, there
is
no
way
to locate
any
given area
on
the
disk.
2.
The
disk directory
is
an
index
of
the
names,
loca-
tions,
and
types of
all
the
files
on
the
disk.
3.
A
disk
file is
an individual block
of
information
stored
on
the disk,
under a
filename.
4.
Information
stored in
memory
will
only be there
temporarily.
It
will
be destroyed
if
the
Computer
is
turned
OFF
or
if
you
execute a
NEW, LOAD,
DIS-
KINI,
BACKUP,
or
COPY
command.
(We'll discuss
BACKUP
and
COPY
in
the next chapters). Infor-
mation stored
on
disk will
be
there
permanently.
It
won't be destroyed
if
the Computer's turned
off
or
if
memory
is
cleared.
(Don't leave a disk in the drive
when
you turn the
Computer
off.
We'll
explain
why
in
the next
chapter.)
5.
The
only
way
to
change
the contents of a disk
file is
by
storing different
information
under
the
same
filename.
CHAPTER
3
1.
Turning
the
Computer
ON
or
OFF
while the disk
is
in
its
drive
may
damage
the
disk.
2.
Only
felt
tip
pens
may
be used
to
write
on
the
disk's
label.
Hard
point
pens
and
pencils
may
damage
the
disk
and
garble the information
on
it.
3.
Error
messages
tell
you
that
something
is
wrong
with
either
the
program you
are
running
or the
last
command
that
you
used.
4.
"Write-protecting"
is
a
way
of protecting
your
disks
from
alteration.
It is
done by
putting a
gummed
label
over the write-protect notch.
You can read from
a
"write-protected" disk,
but you
can't
write
to
it.
5.
On
a one-drive system,
insert
the source disk
into
the
drive
and
type
BACKUP0
(ENTER)
.
The Computer
will
ask you
to
insert the destination disk
and
press
(ENTER)
.
This procedure
is
repeated
until
the
Com-
puter prints
OK.
On
a multi-drive system, type the
BACKUP
command
specifying the drive
number
with the source disk
and
the destination disk.
For
example,
BACKUP
TO
1
backs
up
the source disk
(in
Drive
0)
to
the destination disk
(in
Drive
1).
CHAPTER
4
1.
A
file
can be
renamed
with the
RENAME
command.
For example,
RENAME
"OLDFILE/NAM" TO
"NEWFILE/NAM"
renames
OLDFILE/NAM
to
NEWFILE/NAM.
You must
specify
the extension
for
both filenames
so
the
Computer
can
find
them.
2.
You
can
find out
how much
space
you have
remain-
ing
on
the disk
by typing PRINT FREE
(
)
(ENTER)
.
This
will
tell
you the
number
of
granules
left
on
the disk
in
Drive
0.
If
you
are
running
out
of granules,
you
might want
to
KILL
a few
files
or
switch
to
another
disk.
3.
Unless otherwise
specified,
the
Computer
always
uses Drive
0.
This can be changed by typing
DRIVE
1,
which
enables
you
to
access
Drive
1
without hav-
ing
to specify
the
number
in
your
command,
(i.e.,
now DIR
and DIR1 would
both
get
you
the directory
of the disk in
Drive
1.
CHAPTER
5
1.
Buffer
#1
is
a
temporary
storage
area
for
informa-
tion
going
between
the disk
and memory.
2.
A
disk
file
must
be
OPENed
before
any
information
can go
between
the disk
and memory.
3.
A
disk
must
be
CLOSEd
so
that the information
still
in
the
buffer will
end up where
it's
supposed
to
and
so
that the
file
can be
reopened. All
files
must
be
closed before
you switch
disks.
4.
A
file
OPENed
for
input allows information
to
go
from the disk
file
into
the
memory
of the
Computer.
A
file
OPENed
for
output allows information
to
go
from
memory
to
the disk
file.
CHAPTER
6
1.
When
you
OPEN
a "sequential access"
file,
you can
only
OPEN
it
for "I" or
"O"—
not both.
You
can't out-
put
to
a
file
opened
for
"I,"
nor can
you
input
from a
file
opened
for "O."
2.
No.
The
file
must
first
be
closed
and then reopened
for input.
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